OBD-II code · Powertrain (generic, extended)

P23A7 Exhaust Heat Exchanger Bypass Valve B Stuck Closed

Same as P23A6 with bypass valve B stuck closed - exhaust always passes through the heat exchanger.

Is it safe to drive with P23A7?

Usually safe to drive in the short term. Get it diagnosed when convenient, sooner if the car drives differently.

Common causes

  • Most likelyValve stuck closed
  • Less likelyCarbon or debris buildup preventing free movement
  • Less likelyComponent wear with age - mechanical play

Repair at a glance

Difficulty
Medium
DIY friendly
Best left to a mechanic
Typical labour
1.5–4 h
Emissions test
Likely to fail
Parts involved
Exhaust Bypass Valve B

Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.